Increased risk of subsequent melanoma after first melanoma diagnosis

Source: 2 Minute Medicine, February 2015

1.Patients with a history of familial or sporadic primary melanoma(s) had a 2- to 3-fold increased risk for subsequent melanoma.

Evidence Rating Level: 2 (Good)

Study Rundown: Melanoma is a deadly form of skin cancer. Patients who have multiple melanomas or a family history of melanoma may harbor a mutation in the CDKN2A gene, which increases risk for subsequent melanomas. CDKN2A mutations are present in higher frequency in those with 3 or more melanomas. Therefore, establishing the risk of subsequent melanoma in patients with 2 or more previous melanomas may identify a high-risk cohort that could possibly benefit from increased surveillance and/or genetic testing. Authors found that patients with sporadic or familial melanoma had a stable 2- to 3- fold elevated risk for subsequent melanoma after a first melanoma. This study’s findings were strengthened by the large population-based cohort design. However there were a small number of cases with 3 or more previous melanomas, which limited the accuracy of the standardized incidence ratios in this cohort.

Relevant Reading: Increased risk of second primary cancers after a diagnosis of melanoma

In-Depth [prospective cohort]: Using the Swedish Family Cancer database, authors collected 65,429 patients with a diagnosis of in situ or invasive melanoma between 1958 and 2010. Standardized incidence ratios (SIR) were calculated to assess melanoma risk by comparing incidence of subsequent melanoma in patients who had been diagnosed with their 1st-4th melanoma to the risk of first melanoma within the Swedish population. The SIRs for patients with 2 previous melanomas for a patient with familial melanoma or sporadic melanoma were 2.8 (95% CI, 2.3-3.4) and 2.5 (95% CI, 2.3-2.7), respectively. In both familial and sporadic cases of melanoma, patients younger than 40 were more likely to have subsequent melanomas (SIR, 4.7 [95% CI, 3.9-5.6]) and (SIR, 5.3 [95% CI, 4.3-6.4]), respectively. The SIR of second melanoma in patients with family history of melanoma between the 4th and 5th year post-diagnosis was notably high at 19 (95% CI, 10-31).